| Since the concept of structural control was put forward,vibration control technology has developed rapidly,there are many methods and applications have been studied.Vibration control can be roughly divided into active,semi-active and passive control according to the need of energy input.Active vibration control and semi-active vibration control need energy input for operation.They perform well at vibration controlling but the devices are complex and the reliability is hard to be guaranteed in complicated surroundings.Passive vibration control running without energy,so the passive vibration control devices are simpler and more reliable than active and semi-active devices.However,lots of passive vibration control devices use traditional materials,which material properties are fixed,so passive vibration devices have difficulty in adapting environmental changes.Shear thickening fluid(STF)is intelligent material,whose viscosity varies with the shear rate,and this viscosity variation requires no energy input.In this study,STF is used as damping material of passive vibration control device.A damper based on STF is designed and made.The mechanical properties of STF damper is studied by mechanical test and numerical simulation,and the effect of structure and size parameters on mechanical properties are studied.The rheological properties of STF is analyzed,and application of rotational damper is put forward.The ball screw is used as the transmission component to transform the vibration into rotation,and the shear rate of STF can be increase by the structure of rotational damper.Then STF is prepared and its rheological properties are tested.The theoretical model of the rotational STF damper is established according to the constitutive relationship model of STF.The structural parameters of the damper are determined with the help of theoretical model and then the rotational STF damper has been made.In order to analyse the mechanical properties of the rotational STF damper,this study load the damper at different rotational speeds.It is found that the mechanical properties of damper was significantly affect by the rotational speed.The numerical simulation model of rotational STF model is established,and the reliability of the numerical simulation results is verified by compared with the results of mechanical test.Then,the mechanical properties of the rotational STF damper under dynamic loading are studied by numerical simulation.It is found that both the excitation frequency and the amplitude have effects on the energy dissipation capacity of the rotational STF damperIn order to optimize the working mode of the damper,this study design a new structure of rotational damper.The mechanical characteristics of this damper are studied by numerical simulation.It is found that the maximum damping torque and energy dissipation capacity of rotational damper are improved after changing the structure.The influence of structural parameters of rotational STF damper on mechanical properties and working interval is studied by numerical simulation analysis.Taking Taft seismic wave as an example,the appropriate combination of structural parameters is selected after the range of load is determined,so that the performance of rotational STF damper can be fully exerted. |
